Thomas Herbert, 8th Earl of Pembroke
|The Right Honourable
The Earl of Pembroke and Montgomery
Thomas Herbert by John Greenhill
|First Lord of the Admiralty|
|Monarch||William III and Mary II|
|Preceded by||The Earl of Torrington|
|Succeeded by||The Lord Cornwallis|
|Lord Privy Seal|
|Preceded by||In Commission
Last held by Lord Halifax
|Succeeded by||The Viscount Lonsdale|
|Lord President of the Council|
18 May 1699 – 29 January 1702
|Preceded by||The Duke of Leeds|
|Succeeded by||The Duke of Somerset|
9 July 1702 – 25 November 1708
|Preceded by||The Duke of Somerset|
|Succeeded by||The Lord Somers|
Thomas Herbert, 8th Earl of Pembroke and 5th Earl of Montgomery KG PC PRS (c. 1656 – 22 January 1733), styled The Honourable Thomas Herbert until 1683, was an English and later British statesman during the reigns of William III and Anne.
Herbert was the third son of Philip Herbert, 5th Earl of Pembroke and his wife Catharine Villiers, daughter of Sir William Villiers, 1st Baronet. Both of his brothers having died without a male heir, he succeeded to the earldoms in 1683.
From 1690 to 1692 Pembroke was First Lord of the Admiralty. He then served as Lord Privy Seal until 1699, being in 1697 the first plenipotentiary of Great Britain at the congress of Ryswick. On two occasions he was Lord High Admiral for a short period; he was also Lord President of the Council and Lord Lieutenant of Ireland, while he acted as one of the Lords Justices seven times; and he was President of the Royal Society in 1689–1690. He is the dedicatee of John Locke's An Essay Concerning Human Understanding and Thomas Greenhill's The Art of Embalming".
Marriages & progeny
He married thrice:
- Firstly in 1684 to Margaret Sawyer, only daughter of Sir Robert Sawyer of Highclere Castle by his wife Margaret Suckeley, by whom he had seven sons and five daughters:
- Henry Herbert, 9th Earl of Pembroke (c. 1689–1750), eldest son and heir
- Hon. Robert Sawyer Herbert (d. 1769), who inherited Highclere Castle
- Hon. Charles Herbert
- Hon. Thomas Herbert (c.1695–1739)
- Maj-Gen. Hon. William Herbert (c.1696–31 March 1757), married Catherine Elizabeth Tewes (- 28 August 1770) and had Henry Herbert, 1st Earl of Carnarvon, who inherited Highclere Castle from his uncle
- Hon. John Herbert
- Hon. Nicholas Herbert (c.1706–1775)
- Lady Catherine Herbert (d. September 1716), wife of Sir Nicholas Morice, 2nd Baronet
- Lady Margaret Herbert (d. 15 December 1752)
- Lady Elizabeth Herbert
- Lady Anne Herbert
- Lady Rebecca Herbert, wife of William Nevill, 16th Baron Bergavenny
- Secondly he married Barbara Slingsby (d. 1 August 1721), daughter of Sir Thomas Slingsby, 2nd Baronet and widow of John Arundell, 2nd Baron Arundell of Trerice (1649–1698), of Trerice, Cornwall, by whom he had one daughter:
- Lady Barbara Herbert (d. 27 December 1752), who on 3 October 1730 married Edward Dudley North.
- Thirdly he married Mary Howe (d. 1749), sister of Scrope Howe, 1st Viscount Howe, without progeny. She subsequently married John Mordaunt, MP.
- Pedigree of Arundell of Trerice, Vivian, J.L., ed. (1887). The Visitations of Cornwall: comprising the Heralds' Visitations of 1530, 1573 & 1620; with additions by J.L. Vivian. Exeter: W. Pollard, p.14 
- Doyle, James William Edmund (1886). The Official Baronage of England: showing the succession, dignities, and offices of every peer from 1066 to 1885, Vol. III. London: Longmans, Green & Co. Retrieved 2007-01-25.
- Collins, Arthur (1812). Peerage of England. F. C. and J. Rivington. pp. 142–143. Retrieved 2007-11-03.